From: Jeff Layton <jeff.layton@primarydata.com>
Date: Fri, 4 Jul 2014 08:14:49 -0400
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: linux-nfs@vger.kernel.org
Subject: Re: [PATCH v3 015/114] nfsd: Allow struct nfsd4_compound_state to
 cache the nfs4_client
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On Thu, 3 Jul 2014 18:31:15 -0400
Jeff Layton <jeff.layton@primarydata.com> wrote:

> On Thu, 3 Jul 2014 17:35:26 -0400
> "J. Bruce Fields" <bfields@fieldses.org> wrote:
> 
> > On Thu, Jul 03, 2014 at 04:32:59PM -0400, J. Bruce Fields wrote:
> > > On Mon, Jun 30, 2014 at 11:48:44AM -0400, Jeff Layton wrote:
> > > > We want to use the nfsd4_compound_state to cache the nfs4_client in
> > > > order to optimise away extra lookups of the clid.
> > > > 
> > > > In the v4.0 case, we use this to ensure that we only have to look up the
> > > > client at most once per compound for each call into lookup_clientid. For
> > > > v4.1+ we set the pointer in the cstate during SEQUENCE processing so we
> > > > should never need to do a search for it.
> > > 
> > > The connectathon locking test is failing for me in the nfsv4/krb5i case
> > > as of this commit.
> > > 
> > > Which makes no sense to me whatsoever, so it's entirely possible this is
> > > some unrelated problem on my side.  I'll let you know when I've figured
> > > out anything more.
> > 
> > It's intermittent.
> > 
> > I've reproduced it on the previous commit so I know at least that this
> > one isn't at fault.
> > 
> > I doubt it's really dependent on krb5i, at most that's probably just
> > making it more likely to reproduce.
> > 
> > --b.
> 
> Bruce,
> 
> Does this patch help? I suspect this is where the bug crept in, but I'm
> unclear on why it would be intermittent...
> 
> FWIW, this all gets cleaned up in a later patch that changes how the
> refcounting on lock and openowners works.
> 

I was finally able to reproduce this after a running the cthon lock
tests in a loop, with krb5i. With the patch that I sent earlier, I was
able to run 100 iterations of it without a failure, so I think that was
the bug.

Cheers!
-- 
Jeff Layton <jlayton@primarydata.com>